Spot light source apparatus have conventionally been configured such that they comprise a light-collecting mirror for collecting light emitted from a lamp, whereas the light collected by the light-collecting mirror is made incident on an end portion of a fiber bundle inserted in a fiber insertion slot. Also, such a spot light source apparatus comprises a shutter plate for keeping the light collected by the light-collecting mirror from being incident on the end portion of the fiber bundle, which turns ON/OFF the light incident on the end portion of the fiber bundle. As a conventional spot light source apparatus, one disclosed in Japanese Patent Publication No. HEI 5-22212 also exists.
In the above-mentioned spot light source apparatus, a rotary solenoid is used for driving the shutter plate. Since the rotary solenoid operates by converting a magnetic force into a rotational motion, its operating noise is loud. Also, large vibrations occur when the shutter plate is operated, whereby screws are likely to come loose, for example, thus causing reliability to lower upon long-time driving, and so forth.
Also, during when light emitted from the lamp is turned OFF by the shutter plate, this light is wasted, whereby the emitted light cannot be utilized effectively.
Further, in the case where the quantity of light incident on the end portion of the fiber bundle is to be adjusted, it is necessary for the optical path to be particularly provided with a stop mechanism or the like, and a motor or the like for driving this stop mechanism is also needed.
It is an object of the present invention to provide a spot light source which can effectively utilize light emitted from a discharge lamp.